Thyroid Function Abnormalities in the Acute Phase of COVID-19: A Cross-Sectional Hospital-Based Study From North India

Introduction Viral illnesses like mumps, cytomegalovirus (CMV), and Cocksakievirus have been shown to affect the endocrine system, specifically the thyroid as a product of their systemic inflammatory process. The thyroid gland, having high levels of angiotensin-converting enzyme 2 (ACE2) is also predisposed to dysfunction due to coronavirus disease 2019 (COVID-19). Methodology A cross-sectional study was conducted using retrospective data of thyroid function tests in patients with COVID-19. Results The majority of patients with COVID-19 had normal thyroid function while low serum T3, seen in 47.3% of patients with severe disease, stood out as the most common thyroid abnormality in the acute phase of the disease. The disease severity was seen to correlate with the extent of thyroid function abnormalities, with severely diseased patients having lower T3 values and normal to low thyroid-stimulating hormone (TSH) values. Furthermore, a significant negative correlation was seen between TSH and the bio-inflammatory marker, C-reactive protein (CRP). Conclusion The acute phase of COVID-19 affects thyroid function in direct correlation with the severity of the disease.